Melting apparatus



March 20, 1945. w RODENACKER 2,371,916

MELTING APPARATUS Filed May 3, 1941 2 Sheets-Sheet l m 1 g 1- ---I aINVENTOR ATTORNEY March 945- .w. RoDENAcKER I MELTING APPARATUS FiledMay 3, 1941 2 Sheets-Sheet 2 VVOZ/ Rodenac'er lNVENTOR 1 %//W ATTORNEYPatented Mar. 20, 1945 MELTING APPARATUS Wolf Rodenacker,Berlin-Zehlendorf, Germany;

vested in the Alien Property Custodian Application May 3, 1941, SerialNo. 391,751 In Germany January 16, 1940 1 Claim.

My present invention relates to improvements in method and apparatus formelting the bits of organic compositions thermoplastic and fusible at ahigh temperature. More particularly, it re lates to an improved methodfor producing foils, films, and the like from fusible high molecularweight linear polymers.

Organic materials thermoplastic and fusible at a high temperature can.be worked up at a great speed into films, ribbons, and filaments or byin jection molding. The employment of great speeds is, however, limitedby the melting velocity of the organic composition. Owing to the lowthermal conductivity of most of the compositions the heat-conductingsurfaces must be made very large. It is therefore necessary to use largemelting vessels which require extensive heating as they are to be keptat high temperatures. A further disadvantage of the large meltingvessels resides in the fact that large amounts of molten material arecontinuously maintained therein. A large volume of composition must,therefore, be maintained in the molten condition in which casedificulties are encountered on account of the sensitivity to heat ofmost of the fusible organic compositions.

It is an object of my present invention to provide an improved methodfor melting the bits of organic compositions of the kind mentioned aboveby which a considerable reduction of the melting apparatus and of theamount of heat is position in any form is introduced. At the end or theconduit l the composition is continuously forced, for instance, by aweight laid on it, against a, drum 2 toothed like a milling cutter. Saiddrum is kept at the melting temperature by an electric heating element 3obtainingthe current by means of sliprings t. The exact adjustment ofthe temperature is, for instance, eiiected by heat transfer to a pumpbody which is maimtained at a constant temperature by a controlmechanism. The rotatable drum 2 is driven by a shaft 5 and thus removesthe just melted end of the rod whereupon the rod is forced againstanother hot surface. The drum can be toothed in such a manner that whenthe solid rod contacts it, the pro-heated composition is simulta neouslycut into chips. The molten mass is transferred with a part 5 of the drum2 to a pump l shownas a gear pump, part 6 being a worm. The thread ofthe worm is so constructed that a pressure which efiects a completefilling of the toothed wheels is produced for the pump. The

reached. Further objects will become apparent from the reading or thefollowing description.

The objects of the invention are accomplished by using a moving heatingbody adapted to melt thebits of an organic material and connected with adevice for feeding the material to be melted and, if required, amechanism for feeding the molten composition.

In order to more clearly define this invention, reference is made to theaccompanying drawings in which:

Figure l is a front sectional elevation of the melting deviceconstructed in accordance with and embodying the preferred form of myinvention,

Figure 2 is a side sectional elevation of the device shown in Figure 1,

Figure 3 is a front .elevational view partly in section of a meltingdevice suitable for the production of films, and

Figure 4 is a side sectional elevation of the device shown in Figure 3.

Referring to the drawings, numeral l designates a conduit through whichthe organic compitch is, for example, made progressive for this purpose.To this pressure a further pressuresnay be added. An inert gas, which isnecessary to exclude the air from the melting chamber is pressed intothe storing vessel. It is, however, also possible to employ a meltingdevice with open filling funnel if, for example, carbon dioxide is usedfor driving-out the air, the pump 7 serves automatically to control thefeed of the molten mass to the spinneret l, for if a. greater portion ofthe composition is melted than that removed by thepump, the level of themelt rises and the heat transfer is solely efiected by conduction ofheat from the walls of the conduit l. The rising of the'level of melttherefore effects a lowering of the output. The pump accordinglyregulates the charge as well as the discharge automatically.

The method of the invention can also be carried out in a form other thanthat shown in Figures 1 and 2. A melting device as described above maybe used in spinning processes for producing filaments or ribbons, incasting to form films and thick plates and in injection molding. Themelting device is constructed dependent upon the amount and form of thecomposition and the size of the single apparatus which must correspondto the machines for further treating the molten product. The material tobe worked up may be employed in any form, for instance, as endless rodsor ribbons, strips, cubes, or in granulated or powdered form. As devicefor feeding the prod- -uctin the conduit to the melting drums racks arepositioned which are provided with saw teeth and adapted to move backand forth. Racks are especially suitable-for'feeding products in pieces.The feeding means may also comprise lateral belt conveyers. Forgranulated or powdered materials worms are preferably suitable. Themelting drums must depend in number and size upon the desired power. Itis also evident that the grooving of the elements and the condition oftheir surfaces must correspond to the form of the materials to betreated.

In Figures 3 and 4 a device is shown which is suitable for producingarticles having large areas as, for instance, films. The material whichis introduced into the vessel 8 falls on the melting drums Lworking inboth directions. The drums are connectedwith the feeding worms inconstructed as helical pumps engaging into one another. The worm orhelical. pump produces a pressure by which the toothed wheels I Imounted together with the worms and milling cutters on the same shaftare filled. The gear pump feeds the melt into a distributing conduit I!from which it is forced into a casting tube IS. A corresponding meltingdevice can be constructed for a spinning apparatus having a great numberof spinnerets.

The advantage of the device according to the invention resides in thefact that the part which is to be maintained at a high temperature isespeciaily small whereby the amount of heat necessary for melting thecomposition can be considerably decreased. This is in particular ofimportance when temperatures of above 200 0. must be kept whichareobtained in most cases by electrical heating. A further greatadvantage is the regulated melting procedure in which the controllingmember simultaneously effects the conveyance of the material.

The melting device of this invention is especially suitable iorproducing foils, films, and the like from fusible linear high molecularweight polymers such as polyamides and polyurethanes.

What I claim is:.

In an apparatus for melting a loose mass of organic composition having alow thermal conductivity, a vertical conduit for receiving and feedingsaid composition, a pair of interengaging longitudinally-ribbed meltingdrums transverse- 1y disposed in the path of said conduit and working inopposite directions, said drums having at one end registering helicalfeeding worms. and a gear pump to receive and feed the melt downwardlyfrom the helical pump.

WOLF RODENACKER.

